Well after read some positive posts in this thread I finally made up my mind by taking this promotion and booked 6 Marriott stays for a vocation to Cal. However, eventually only two of them are given the bonus miles, with the rest just ordinary (and mediorce) miles. I tried to call Delta or email them by the reply I've got are as follows:
1) I can only get 5000 miles for each flight (not stay)
2) the bonus miles will be posted after the promotion ends (Jan 31st, 2011)

However, I've already have two of them posted and I am wondering why those Delta representatives are so careless to see that...

Anyone knows a better idea of how to retrive those miles? PS: I am just a Delta silver.